How’s this for timing? NASA’s New Horizons spacecraft is winging past Pluto this morning (July 14) exactly 50 years after the first robotic visit to Mars.

On July 14, 1965, NASA’s Mariner 4 probe flew by the Red Planet, becoming the first spacecraft ever to capture up-close looks at another planet. (NASA’s Mariner 2 spacecraft gathered data but no images when it zoomed past Venus in December 1962.)

“You couldn’t have written a script that was better,” New Horizons principal investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado, told Space.com.

Five spacecraft are circling Mars and creeping across its ruddy surface, looking for traces of long-gone waters and signs that the cold, arid planet may once have been hospitable to life. The robotic martian invasion – three orbiters and two six-wheeled rovers – has already uncovered strong evidence that water once flowed on Mars and is now locked in subsurface ice. But big questions about water on Mars remain. When did it flow? How long did it last? How much was there? Where did it come from? Where did it go? Perhaps the most tantalizing question: Were there long-lived watery environments where microbial life could have gained a foothold?